# Regular Expression Pattern

(Redirected from regular expression)

A regular expression pattern is a pattern matching expression in a regular formal language (that can be accepted by a finite state machine).

**Context:**- It can range from (typically being) a Regular String Expression to being a Regular Graph Expression.
- It can be processed by a Regular Expression Processor.

**Example(s):**- a String-based Regular Expression Pattern, such as
`/a[^b][cd]e/`

- a Graph-based Regular Expression Pattern, such as one to describe a graph path or a subgraph.

- a String-based Regular Expression Pattern, such as
**Counter-Example(s):****See:**Graph Matching Pattern, Formal Language, Perl Regular Expression.

## References

### 2009

- http://en.wiktionary.org/wiki/regular_expression#Noun
- 1. (computing theory) A concise description of a regular formal language with notations for concatenation, alternation, and iteration (repetition) of subexpressions.
- 2. (computing more generally) Any pattern for text matching or searching, frequently offering more or less functionality than a theoretical regular expression.